1. Field of the Invention
This invention relates to an interactive graphic system which can record predetermined lines, symbols or marks directly on the plotting surface by inputting plotting information.
2. Description of the Prior Art
Heretofore, in order to plot figures or graphs on a recording sheet, the following two methods have been employed. In one of the methods, a computer or a calculator and a plotter are combined, so that the coordinate signals of figures or graphs stored in the computer or the calculator are successively applied to the plotter to plot the figures or graphs. In the other method, a cathode-ray-tube display unit and a plotter are combined, so that a picture on the display unit is hard-copied on the plotter.
However, these conventional methods are disadvantageous in that, since the plotter itself can draw simple figures only, the provision of an external unit such as a computer, a calculator or a cathode-ray-tube display unit is essential for drawing figures or graphs, and the combination of the external unit and the plotter makes the entire device considerably bulky.
Furthermore, the operation of the computer or calculator is not simple. That is, since the computer or calculator is designed for general purposes, it is necessary to carry out intricate operations by referring to an operating manual containing a large amount of description even in drawing a relatively simple figure or symbol. Accordingly, the conventional methods are disadvantageous.
On the other hand, in a special calculator or in a cathod-ray-tube display terminal, a long instruction word or sentence which is frequently used is assigned to one key thereby simplifying the plotting operation. However, the operation of assigning such a word or sentence to the key is intricate.